Sealed-in contact device



April 25, 1961 R. NITSCH SEALED-IN CONTACT DEVICE 2 Sheets-Sheet 1 Filed Dec. 29, N58

Fig.1

m mix L April 25, 1961 R. NITSCH SEALED-IN CONTACT DEVICE 2 Sheets$heet 2 Filed Dec. 29, 1958 fizz/( 222a:- Eadolf #1230 SEALED-IN CONTACTDEVICE Rudolf Nitsch, Munich, Germany, assignor to Siemens and Halske Aktiengesellschaft Berlin and Munich, a corporation of Germany Filed Dec. 29, 1958, Ser. No. 783,412

Claims priority, application Germany Jan. 15, 1958 7 Claims. (Cl. 200-87) This invention is concerned with a contact device, especially a device containing sealed-in contacts, comprising contact springs which are operatively actuated responsive to magnetic flux flowing therethrough.

The communication art employs for various purposes contacts which are operatively controlled by current flowing thereover. This is, for example, the case incident to holding and releasing connections. Circuits extending by way of switch contacts are in such cases maintained for the duration of a connection and interrupted at the conclusion theerof, thus requiring maintaining the switch contacts for the duration of the connection in operated position and restoring them at the conclusion of the connection. The current flowing over the switch contacts accordingly constitutes a criterion for the operation of the corresponding switch. There are other instances in which the operation of contacts is controlled by current flowing thereover.

The problems arising in connection with the above indicated control of contacts have been previously solved by interposing a winding in the circuit, such winding acting in the manner of a relay winding and thereby causing the desired contact actuation responsive to current flowing therein. Such relay windings are oftentimes undesirable, especially in the case of lines over which alternating current is to be transmitted. The winding produces in such case a damping that must be equalized by the provision of some auxiliary switching elements.

The invention shows a way for realizing the desired contact operation depending upon current flowing over contacts of particular construction, namely, in connection with contacts having contact springs carrying a magnetic flux for effecting operative actuation thereof. Contacts of this kind include the so-called sealed-in or tube protected contacts.

The various objects and features of the invention will appear from the description which is rendered below with reference to the accompanying drawings. In the drawings,

Fig. 1 shows an example of a sealed-in or tube protected contact;

Fig. 2 illustrates in schematic manner a sealed-in make contact to aid in explaining the opening operation thereof;

Fig. 3 shows a contact spring in cross-sectional plane indicating the current flow and magnetic flux;

Fig. 4 indicates a magnetic substitution circuit for the arrangement according to Fig. 2;

Figs. 5 and 6 show variants of Figs. 2 and 4;

Fig. 7 shows another variant of Fig. 2; and

Fig. 8 illustrates diagrammatically the manner of holding a closed make contact in actuated position.

The sealed-in or protective tube contact shown in Fig. l comprises a glass tube G into which extend sealed-in contact springs F1 and F2, the inner ends of such contact springs overlapping and forming a centrally disposed States Patent 0 ice working air gap. A contact of this type is customarily actuated by impressing thereon a magnetic field which causes the contact springs F1 and F2 to be drawn together. The magnetic field is usually produced by a coil winding (not shown) surrounding the glass tube G.

In accordance with the invention, a control flux is conducted over the contact springs in the operatively actuated position thereof and actuating current is caused to flow thereover for the actuation of the contact, such current affecting the control flux due to flux displacement in the contact springs so as to effect contact actuation.

The invention may be applied to effect diverse modes of contact operation. As examples may be mentioned the opening of a closed make or working contact and holding a make contact in operatively actuated or closed position.

A closed make contact may be held inoperatively actuated or closed by conducting control flux as a holding flux over the corresponding closed contact springs, and may be caused to open by switching in actuating current so as to weaken the holding flux due to flux displacement and thus effecting the opening of the contact. In holding a closed make contact in operated position, the control flux consists of a holding flux which is conducted to the ends of the contact springs at the air gap and of a compensation flux which is opposed to the holding flux and conducted to the outwardly disposed ends of the contact springs, such compensation flux leaving the contact unaffected, until the actuating current is switched in, which weakens the compensation flux due to flux displacement to such extent that the holding of the contact in closed position is effected by the holding flux.

The opening of a closed make contact may be explained with reference to Fig. 2 showing in diagrammatic manner a sealed-in make contact comprising contact springs F1 and F2 and by reference to Fig. 3, indicating the current flow and the magnetic flux. The contact is provided with three coils, namely, a centrally disposed exciting coil A and holding coils H one disposed at the outwardly positioned end of the respective contact springs. Energization of the exciting coil A causes in known manner mutual attraction between the contact springs F1 and P2, drawing these springs together into closed position, the springs being thereafter held in closed position by the energization of the holding coils H, the energization of the holding coils alone being insufficient to effect contact closure. The holding coils deliver a holding flux pit, acting as a control flux, which is closed by way of the actuated contact springs and a magnetic return path R interconnecting the outwardly positioned ends of the contact springs F1 and F2. Upon switching in the actuating current I, the flux i produced by this current will be superimposed on the holding fiux h, the first noted flux pi extending within the contact springs about the current flow, that is, perpendicular to the holding flux 5h which extends in the direction of the longitudinal axis of the contact springs, that is, parallel to the current flow. The superimposing of the fluxes causes displacement of the holding flux h which is practically equivalent to an increase of the magnetic impedance in the magnetic circuit of the holding flux. The holding flux h is consequently weakened and the contact opens. The actuating current is thereby disconnected which however remains without effect since the holding flux h alone is insufficient to close the opened contact.

The actuating current referred to above may be a current impulse of sufficient strength to effect the opening of the contact. Such current impulse may be added to the operating current which is to be controlled by the contact, that is, in the initially mentioned use of the arrangement in the communication art, the impulse may be superimposed upon alternating speech currents flowing in the corresponding circuit.

Fig. 3 shows a cross-sectional view of a contact spring, a current I flowing in such spring centrally thereof in a direction perpendicular to the plane of the drawing. Such current, depending upon the density thereof, permeates the entire cross-sectional area of the contact spring. About this current I closes ring-like the flux i eflected thereby. Since the holding flux h extends parallel to the current paths 1, that is, likewise in a direction perpendicular to the plane of the drawing, the fluxes i and lz will flow mutually perpendicularly, thereby effecting the previously mentioned flux displacement of the holding flux 4:11 which is practically equivalent to an increase of the magnetic impedance of the contact spring for the holding flux 5h.

The action of the increase of magnetic impedance in the contact spring, responsive to the flow of actuating current, is the greater the greater the impedance portion of the contact springs at the magnetic circuit for the holding flux h. A large impedance portion may be obtained by the action of the magnetic return path R over which the holding flux h can close by way of a magnetic conductor with low magnitude impedance.

Fig. 4 shows the magnetic substitution circuit for the arrangement according to Fig. 2. The magnetic circuit is formed by the resistances R of the contact springs between which lies the impedance R1 of the air gap (or the closed contact point) and by the impedance Rr of the magnetic return path. In this circuit are placed the excitations 0h delivered by the holding coils and acting as magnetic sources. It will be easily seen from this substitution circuit that the alteration of the holding flux will be the greater, the greater the portion of the impedances R1 and the total impedance of the magnetic circuit.

The action of the return path may be increased by the provision, between the magnetic sources for the holding flux h (holding coils H in Fig. 2) and the working air gap, of a magnetic shunt extending from the corresponding contact spring to the magnetic return path. A suitable embodiment is indicated in Fig. 5.

Referring to Fig. 5, the magnetic return path R is carried between the holding coils H and the air gap close to the contact springs F1 and F2, forming at the corresponding places magnetic shunts N. Fig. 6 shows the corresponding substitution circuit. As will be seen from this circuit, there is provided at the contact point, between the magnetic sources (iii and the magnetic impedance R1, the longitudinal impedance Rf and the leakage Rs. This leakage is efrected by the shunts N, the stray flux s flowing over the leakage path. The operation of the arrangement corresponds to that of a T-element with longitudinal impedance and transverse leakage path. The arrangement effects an increase of the magnetic induction in the contact springs, thereby increasing the portion of the spring irnpedance Rf with respect to the total impedance. The holding coils deliver the flux which is subdivided into the holding flux h and the stray fluxes s.

Fig. 7 shows a variant of Fig. 2 in which the holding flux h is produced by permanent magnets Mh which are interposed between the magnetic return path R and the outwardly positioned ends of the contact springs F1 and F2. The flux produced by the permanent magnets Mh is in the open position of the contact springs F1 and F2 insuflicient to cause closure thereof, but is sufiicient to hold the two contact springs in closed position. The function of the contact shown in Fig. 7 corresponds completely to that of the embodiment illustrated in Fig. 2. An energizing or actuating coil has been omitted in Fig. 7 since it is possible to produce the required excitation in difierent manner.

The holding of a closed make contact in its closed position may be explained with reference to Fig. 8. In Fig. 8, the control flux is composed of a holding flux ph and a compensation flux ek. The holding flux is produced by a permanent magnet Md which is disposed adjacent the air gap in such a manner that the flux d emanating from its poles is conducted directly to the inner ends of the contact springs F1 and F2 at the working air gap. The compensation flux is produced by two permanent magnets Mk which are interposed between the magnetic return path R and the outwardly positioned ends of the contact springs F1 and F2. The compensation flux k is in this manner conducted to the outwardly positioned ends of the contact springs.

The holding flux d and the compensation flux k are at the place where they are superimposed, that is, in the region of the working air gap, oppositely oriented. This causes a weakening or compensation of the fluxes so that they remain normally without eflect on the contact springs. However, when the actuating current I is switched in, re sponsive to closure of the contact by suitable auxiliary excitation, for example, by means of an exciting winding, a flux displacement will be produced in the contact springs F1 and F2 which will act substantially only with respect to the compensation flux 5k since the contact springs F1 and F2 form an essential portion in the magnetic circuit for the compensation flux k. The action of the flux displacement on the holding flux d is comparatively relatively slight since such flux is conducted only over very short parts of the springs F1 and F2 so that the impedance change in the magnetic circuit for the holding flux pd is rather slight. The result of the weakening of the compensation flux 4 k is that the holding flux d can now become fully operative to eifect the holding of the closed contact. The auxiliary excitation required for the contact closure can accordingly be disconnected. The holding of the contact is thus made dependent on the actuating current I flowing over the closed contact. Disconnection of the actuating current I will cause opening of the contact.

It is understood, of course, that magnetic shunts may be provided in the return path R of Fig. 8 in a similar manner as explained in connection with Fig. 5. The required fluxes may also be produced by coils instead of by permanent magnets.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

I claim:

1. A device for controlling the operation of a contact arrangement having contact springs carrying magnetic flux causing actuation thereof depending upon current flowing thereover, comprising means for conducting over said contact springs in one operated position thereof a control flux, and means for conducting over said contact springs an actuating current, said actuating current causing an annular flux to flow in the contact springs, such annular flux effecting displacement of said control flux in said contact springs so as to effect control of said contact springs.

2. A device according to claim 1 for controlling the operation of the contact springs of a make contact from closed to open position thereof, wherein said control flux is operative as a holding flux to maintain said contact springs in closed position, said annular flux weakening said holding flux due to flux displacement so as to effect opening of said contact.

3. A sealed-in make contact device having a protective tube and contact springs extending thereinto from opposite ends of the tube with their inner ends overlapping across a working air gap, said contact springs carrying magnetic flux causing operative actuation thereof depending upon current flowing thereover, comprising permanent magnet means for producing a control flux, said permanent magnet means disposed adjacent said working air gap and extending with respect thereto so that the control flux emanating from the poles thereof is conducted direct- 1y to the inner ends of said contact springs at said air gap, to flow over said contact springs in the operatively closed position thereof, means for conducting to said contact springs at the outwardly disposed ends thereof a compensation flux oriented oppositely to said control flux, means for connecting to said contact springs an actuating current which is Operative to weaken said compensation flux due to flux displacement, whereby said control flux becomes operative to operate as a holding flux to maintain said contact springs in closed position, means forming a magnetic return path for said contact springs, and means for interconnecting the outwardly positioned ends of said contact springs over said return path so as to allocate to said contact springs a substantial portion of the impedance of the magnetic circuit for said holding flux and said compensation flux.

4. A sealed-in make contact device having a protective tube and contact springs extending thereinto from opposite ends of the tube with their inner ends overlapping across a working air gap, said contact springs carrying magnetic flux causing operative actuation thereof depending upon current flowing thereover, comprising means for conducting control flux to the inner ends of said contact springs at said air gap, to flow over said contact springs in the operatively closed position thereof, means for conducting to said contact springs at the outwardly disposed ends thereof a compensation flux oriented oppositely to said control flux, means for connecting to said contact springs an actuating current which is operative to weaken said compensation flux due to flux displacement, whereby said control flux becomes operative to operate as a holding flux to maintain said contact springs in closed position, means forming a magnetic return path for said contact springs, permanent magnet means connected to said return path for respectively producing said holding flux and said compensation flux, and means for interconnecting the outwardly positioned ends of said contact springs over said return path so as to allocate to said contact springs a substantial portion of the impedance of the magnetic circuit for'said holding flux and said compensation flux.

5. A device for controlling the operation of the contact springs of a closed make contact arrangement having contact springs carrying magnetic flux causing actuation thereof depending upon current flowing thereover so as to maintain such contact in closed position, comprising means for conducting a control flux to the ends of said contact springs which define the working air gap thereof, means for conducting to the other ends of said contact springs compensation flux oriented oppositely to said control flux, and means for conducting over said contact springs an actuating current, said actuating current weakening said compensation flux due to flux displacement so as to cause said control fiux'to become operative as a holding flux to maintain said contact springs in closed position.

6. A device according to claim 5, comprising means forming a magnetic return path for said contact springs, and means for interconnecting said other ends of said contact springs by way of said magnetic return path so as to allocate to said contact springs a substantial portion of the impedance of the magnetic circuit for said holding flux and for said compensation flux.

7. A device according to claim 6 comprising means forming between the magnetic sources for said holding flux and for said compensation flux and said working air gap a magnetic shunt extending from one of said contact springs to said magnetic return path.

References Cited in the file of this patent UNITED STATES PATENTS 1,836,725 Proctor Dec. 15, 1931 2,187,115 Elwood et al. Jan. 16, 1940 2,312,669 Nippert Mar. 2, 1943 2,877,315 Oliver Mar. 10, 1959 2,902,558 Peek Sept. 1, 1959 

